1. Field of the Invention
The present invention relates to an intracorporeal substance measuring assembly provided in an embedded type substance sensor for detecting and measuring an intracorporeal analyte, a method of producing the intracorporeal substance measuring assembly, and an embedded type substance sensor using the intracorporeal substance measuring assembly.
2. Description of the Prior Art
Embedded-in-body type sensors are useful for observation of the proceeding of a disease or for monitoring a therapeutic effect in various diseases, and constitute one of the fields which have been actively researched in recent years. Particularly, in treatment of diabetes, blood sugar control based on continuous blood sugar measurement is said to contribute to the retarding of progress of a disease or to a reduction in morbidity of complications.
Many of diabetic patients at present are making it a practice to draw a blood sample by puncturing a finger or the like, to supply the blood sample to a blood sugar meter, and are to read the measured value, for self-control of blood sugar. Such a method, however, has problems in view of pain to the patient and of easiness; the measurement is limited to several times a day, and it is difficult at present to frequently measure the variation in the blood sugar and to grasp the tendency of the variation. From these grounds, it is considered that an embedded type continuous blood sugar meter is highly useful.
As an embedded-in-body type sensor, an apparatus with transmission of signals to and from an instrument embedded in a living body on a wireless basis has been disclosed (refer to U.S. Pat. Nos. 4,550,731 and 4,253,466). According to this technology, a detection device (sensor) having an indicator layer of which the fluorescence property is varied through reaction with glucose reversibly is embedded in a living body, the glucose concentration is measured from the variation in fluorescence amount, and the data is led out to the exterior of the body by way of electromagnetic waves or the like.
In addition, as a material which can be used for the indicator of the detection device, there has been proposed one in which a fluorescent substance capable of reversible coupling with glucose, such as phenylboronic acid, is covalently bonded to polystyrene (refer to U.S. Pat. No. 5,137,833).
Besides, while various saccharide components are present in a living body component, a fluorescent substance capable of specific and reversible coupling with glucose has been proposed (refer to U.S. Pat. No. 5,503,770).
However, these conventional embedded-in-body type sensors have the problems that the substance (indicator substance) for generating fluorescence upon contact with an analyte is deteriorated during use and cannot endure the embedding for a long time and that the accuracy of measurement is low.